It's a progressional modeled loot system. Like many other MMOs. New raid comes out, old raid becomes obsolete it is the cycle that works. It is a proven method that yeilds the best results. Gamers wish they could use any previous raid gear without being at a disadvantage, but the issue is that people will beat the new content maybe once, and then never do it again. Gamers are loot driven, above all things. Few give a damn about lore or beating the mechanics of an encounter. Bungie had a system that was revolutionary, etheric light.... it the got rid of it. I assume it made it too easy to attain max light due to the ease of access. Either way...no one playing old content is intended. That's how these games are designed. And it is not bungie's fault that no one wants to play old content. It's available to everyone, gamers just need sonething more than a "experince" to care